1. Field of the Invention
The present invention relates to a method, system, and article of manufacture for using link send and receive information to select one of multiple links to use to transfer data for send and receive operations.
2. Description of the Related Art
Host systems in a storage network may communicate with a node through multiple paths. The node may be comprised of separate storage clusters or nodes, where each storage cluster is capable of accessing the storage and provide redundancy to access the storage. Hosts may access the attached storage through either cluster. If a storage cluster fails, then the host may failover to using the other storage cluster to access the storage.
The host systems have to select a link or path to use to communicate with another host. One prior art solution is to use round robin load balancing algorithms that try to balance the amount of work even on each link. However, round robin balancing technique may fail to detect and report that throughput on a link is less capable than another link or is degraded, and may also fail to properly balance workloads under certain conditions because data transfer tasks take longer on links having lower data throughput. For instance, if a more capable link is completing work faster, the round robin load balancing algorithm may just as likely select a worse performing link over a better performing link In this way, using a round robin method may result in work backing-up on the slower performing link due to the 50-50 distribution, whereas the better performing link would drain quickly and the number of tasks would grow on the slower link, eventually putting all but an occasional single task on the faster link.
There is a need in the art for improved techniques to select one of multiple links to use to communicate between nodes.